A capsule of the type identified above is known, for example, from WO2010/137955.
The invention is described below with specific reference to its application to a coffee capsule, but it is to be considered as generally applicable to a capsule for any other infusion product.
A coffee capsule typically comprises a cup-shaped body, in particular a body of frustoconical shape, which contains the coffee, and a cover which closes the cup-shaped body. The cup-shaped body is typically made of plastic material. The cover, which is a separate component from the cup-shaped body, is typically also made of plastic material or of an aluminium foil.
In order to produce the coffee/water infusion, the capsule is inserted into a percolation chamber of the coffee machine, where a certain quantity of hot water is injected under pressure into the cup-shaped body of the capsule through a plurality of holes provided in the bottom of the cup-shaped body, so as to mix with the coffee inside the cup-shaped body. The beverage produced by the infusion then exits from the cup-shaped body through a plurality of openings made in the cover of the capsule.
In some known solutions, the beverage exits from the cup-shaped body of the capsule through openings in the cover of the capsule which are produced by the interaction between the cover and a plurality of protruding elements which project inwards from a bottom wall of the percolation chamber of the machine. As a result of the pressure increase inside the cup-shaped body due to the introduction of the pressurized hot water, the cover, which is made for example of an aluminium foil, deforms until it comes into contact with the protruding elements of the percolation chamber. The contact between the protruding elements and the cover causes the cover to be cut in several points thereof. The infusion exits from the capsule through the passages created by these cuts and is conveyed to a final container, such as a coffee cup.
Moreover, as is known, measures are increasingly commonly adopted in coffee machines to facilitate the formation of a “cream”, which is particularly appreciated by coffee consumers. The coffee cream is produced by promoting the formation of an intimate emulsion of air within the coffee infusion leaving the capsule. In order to obtain an acceptable coffee cream it is necessary to prevent air from remaining trapped in bubbles, as this would simply lead to the formation of a coffee froth, which is not at all appreciated by the average consumer.
Special devices, known as “emulsifying devices”, have been devised for fitting to coffee machines in order to promote the formation of the coffee cream. However, the use of emulsifying devices in coffee machines disrupts the overall design of the machines, leading to considerable increases in the manufacturing cost of the machines, as well as to lower reliability of the beverage preparing and delivering process.
There is therefore a particularly strongly felt need to cause formation of the coffee cream by means of the particular shaping of the capsule, rather than by means of an emulsifying device fitted to the machine.